1. Field of the Invention
The present invention relates to a variable quantity control apparatus for a variable radius type scroll compressor, and particularly, to a variable quantity control apparatus for a variable radius type scroll compressor by which a recession amount of an orbiting scroll can be effectively restrained, and also the number of components and assembling processes can be reduced.
2. Description of the Background Art
Generally, a scroll compressor is divided into a fixed radius type scroll compressor in which an orbiting scroll always orbits in an identical trajectory regardless of changes in compressing conditions, and a variable radius type scroll compressor in which an orbiting scroll is recessed with respect to a radial direction in order to prevent a wrap from being damaged when liquid refrigerant, oil, or impurity is inputted into a compression chamber and therefore a pressure in the compression chamber is increased abnormally.
In order to change an orbiting radius of the orbiting scroll in the variable radius type scroll compressor, a bushing, a slide block, or an eccentric bushing may be connected between a rotary shaft and the orbiting scroll.
The present invention is related to the variable radius type scroll compressor in which the eccentric bushing is connected.
As shown in FIG. 1, a conventional variable quantity control apparatus for the variable radius type scroll compressor includes a fixed scroll 2 including a spiral wrap 2a fixed on a main frame 1; an orbiting scroll 3 including a spiral wrap 3a engaged with the wrap 2a of the fixed scroll 2 and disposed between the main frame 1 and the fixed scroll 2; a rotary shaft 4 coupled to a driving motor and to the orbiting scroll so that a rotating force of the driving motor (not shown) can be transmitted to the orbiting scroll 3; and an eccentric bushing 5 inserted into the rotary shaft 4 for transmitting the rotating force of the driving motor to the orbiting scroll 3 and for inducing the orbiting scroll to be recessed when over-compressed.
A driving pin part 4a for transmitting the rotating force generated from the driving motor to the orbiting scroll 3 by inserting the eccentric bushing 5 is eccentrically protruded toward the main frame 1 on a front end surface of the rotary shaft 4, and a pin recess (not shown) in which a lower end of a stopper pin which will be described later is depressed toward opposite direction with a predetermined gap to the driving pin part 4a. 
In addition, the eccentric bushing 5 includes a pin hole 5a, in which the driving pin part 4a of the rotary shaft 4 is inserted, formed on one side, and a pin recess 5b, in which the stopper pin 6 is inserted, formed with a certain gap with the pin hole 5a. 
In addition, an upper half part of the stopper pin 6 is inserted and coupled to the eccentric bushing 5, and a lower half part of the stopper pin 6 is inserted into the pin recess (not shown) disposed on the front end surface of the rotary shaft 4 so as to be rotated to a circumferential direction of the rotary shaft.
And a driving bush 7 is coupled between an outer circumferential surface of the eccentric bushing 5 and an inner circumferential surface of a boss part 3b formed on lower end part of the main frame 1 for transmitting the driving force of the rotary shaft 4 to the main frame 1.
Unexplained reference numeral 2b designates a discharge hole, 2c designates a suction hole, and P designates a compression space.
Hereinafter, operations of the conventional variable quantity control apparatus for the variable radius type scroll compressor will be described as follows.
When the driving motor (not shown) is rotated with the rotary shaft 4 by the applied electric power, the orbiting scroll 3 is orbited over an eccentric distance, and accordingly, a plurality of compression spaces P are formed between the wrap 3a of the orbiting scroll 3 and the wrap 2a of the fixed scroll 2. And the compression spaces P are moved toward a center part by continued orbiting movements of the orbiting scroll 3. A volume of the space is gradually decreased and therefore refrigerant gas is drawn in, compressed and discharged.
At that time, in case that the refrigerant gas drawn in into the compression spaces maintains a normal state, the wrap 3a of the orbiting scroll 3 and the wrap 2a of the fixed scroll 2 are line contacted with each other, and then the both compression chambers form sealed spaces and locations of the eccentric bushing 5 and the stopper pin 6 are maintained.
On the contrary, if liquid refrigerant, oil, or other impurity in excess of a predetermined amount is mixed in the refrigerant gas which is sucked into the compression space P, the pressure in the compression space P is abnormally increased and the orbiting scroll 3 is likely to recess or rotated in reverse. In addition, this inclination is transmitted to the eccentric bushing 5 which is inserted into the boss part 3b of the orbiting scroll 3, and then the eccentric bushing 5 is rotated to the reverse direction of the orbiting scroll""s direction. And during that process, as shown in FIG. 3, the wrap 3a of the orbiting scroll 3 and the wrap 2a of the fixed scroll 2 are separated from each other and the compression gas in the compression space of high pressure HP is leaked to the compression space of low pressure LP. Accordingly, damage of the wraps 2a and 3a by over-compression can be prevented.
However, in the conventional variable quantity control apparatus for the variable radius type scroll compressor described above, an additional stopper pin 6 should be made and post-assembled, and therefore the numbers of components and the assembling processes are increased and manufacturing cost is increased.
Also, the stopper pin 6 restricts the recession of the orbiting scroll 3 by line contacting the respective pin recesses (not shown) (5b) of the rotary shaft 4 and of the eccentric bushing 5. However, the contact area is small, and therefore there is the recess amount of the orbiting scroll 3 is restricted.
Also, when repeated recess mechanisms are performed, the stopper pin 6 has a weak mechanism resistance due to the limitation of the shape.
Therefore, an object of the present invention is to provide a variable quantity control apparatus for a variable radius type scroll compressor by which the number of components and the number of assembling processes are decreased, and therefore manufacturing cost can be reduced.
Also, another object of the present invention is to provide a variable quantity control apparatus for a variable radius type scroll compressor by which a recess quantity of an orbiting scroll can be stably restricted.
Also, still another object of the present invention is to provide a variable quantity control apparatus for a variable radius type scroll compressor which has strong mechanical resistance even if repeated recess mechanisms are applied.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a variable quantity control apparatus for a variable radius type scroll compressor comprising: a rotary shaft coupled to an orbiting scroll for transmitting a rotating force of a driving motor to the orbiting scroll; and an eccentric bushing coupled to a driving pin part of the rotary shaft for transmitting the rotating force of the driving motor to the orbiting scroll and restricting a recess amount of the orbiting scroll.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.